Network Security

You are not secure. The Windows Firewall is not designed to provide the commercial-level of firewall protection that you would find in in a CISCO PIC, Checkpoint, ISA server, etc.

Although why you would be considering a Cisco PIX with a dial-up line is beyond me. You can pick up a hardware appliance, such as a Netscreen firewall, very cheap on the net.

In addition, with a Windows XP acting as a gateway, you are going to be limited to 10 IP connections maximum. This could quickly become an issue depending on the number of clients attempting to connect to our through the device.

Would like to know where you would put the PIX? Behind the PC? I don't think it has an RJ11 interface.
With dial-up, unless you plan to try to stay connected all the time, you are inherently at a lesser risk than broadband simply because you are not always connected, and your IP keeps changing.
Use a good SOHO router with deep-packet inspection, and a software firewall like ZoneAlarm on the gateway PC. Use a name brand anti-virus app and keep it updated on all the PC's.

I must agree with the others, first thing first is I'm confused why anyone on earth would go the route of a Cisco PIX for a dial-up solution, let alone when using Windows XP as the gateway. Cisco PIX units are higher end firewall solutions, from what I gather from your setup it would be wasting money on an overkill solution.

Never trust the WinXP built-in firewall, is very weak and mostly useless.

I say get yourself a decent soho router configure NAT with it make sure it comes with packet inspection (stateful) features, then install either a software firewall solution or you can even buy a lower end SOHO firewall solution like a Sonicwall unit.

You can get a years free copy of eTrust eArmorLE.

It has antivirus and a software firewall. You should have no problems with this solution.

Lee